Topic Overview

Viral load is a measurement of how much HIV is present in your blood. A sample of blood is drawn and sent to a lab for testing. Results are expressed as the number of copies of the virus per millilitre of blood. Each virus is called a "copy" because HIV reproduces by making copies of itself (replicating).

The viral load test gives a more accurate picture than a CD4+ cell count of what the virus is doing in your body at the moment. (The CD4+ test measures the effect HIV is having on your immune system.) The viral load test is used to help decide when to change antiretroviral medicines.